Exactly what Simonclay pointed out. Gears are the least of your worries if you are going V8 power.
If you are keeping the 4cyl for awhile, then the proper gear for 33" tires would be a 4.88 ratio. Whereas the 4.10s that are in it now would be perfect for the V8, except that the rear axle will not handle the torque of a V8.
The front Dana 30 will be fine as it is, providing that you don't exceed the 33" tire.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...